Semi-Persistent Scheduling in Sub-Subframe Operation

ABSTRACT

A scheduling node ( 110 ) transmits, to a radio node ( 105 ) configured for sub-subframe operation, a semi-persistent scheduling (SPS) configuration message ( 210 ) configuring the radio node ( 105 ) for sub-subframe-based SPS. The SPS configuration message ( 210 ) comprises an identifier of the radio node ( 105 ) and indicates a pattern of sub-subframes ( 82 ) in which a resource allocation for the radio node ( 105 ) repeats. The radio node ( 105 ) receives the SPS configuration message ( 210 ) and configures the radio node ( 105 ) for sub-subframe-based SPS according to the SPS configuration message ( 210 ).

TECHNICAL FIELD

Embodiments of the present disclosure generally relate to schedulingradio transmissions and more particularly relate to semi-persistentscheduling of data transmissions to make use of transmission resourcesaccording to a pattern applied to multiple sub-subframes.

BACKGROUND

Many wireless communication systems involve transmission schedulingbetween wireless nodes. In some such systems, a first node sets thetransmission schedule, and other nodes communicating with the first nodeadhere to the transmission schedule. One example of such a transmissionschedule defines when the other nodes may expect the first node totransmit on a downlink. Another example of such a transmission scheduledefines when the other nodes are permitted to transmit on an uplink. Thefirst node may inform the other nodes of the transmission schedulingusing Downlink Control Information (DCI). One particular example of suchDCI may be DCI as defined by the 3GPP standards organization, e.g.,according to 3GPP TS 36.212 V14.0.0 (2016-09). Such DCI may include, forexample, a resource allocation, modulation and coding scheme, and otherinformation useful for decoding transmissions. Other examples of suchDCI may be particular proprietary to the particular wireless technologyused for the communication, or may be defined by other standardsorganizations. By scheduling transmissions, the first node maycoordinate communication between the nodes over a shared wireless medium(e.g., a particular time and/or frequency domain of an air interface).

SUMMARY

Some embodiments herein include a scheduling node that transmits, to aradio node configured for sub-subframe operation, a semi-persistentscheduling (SPS) configuration message configuring the radio node forsub-subframe-based SPS. The SPS configuration message comprises anidentifier of the radio node and indicates a pattern of sub-subframes inwhich a resource allocation for the radio node repeats. In particularexamples, the SPS configuration message configures the radio node forsub-subframe-based SPS that is concurrent with subframe-based SPS inwhich a subframe-based resource allocation repeats according to afurther pattern.

Consistent with the above, embodiments herein include a method oftransmission scheduling implemented by a scheduling node. The methodcomprises transmitting, to a radio node configured for sub-subframeoperation, an SPS configuration message configuring the radio node forsub-subframe-based SPS. The SPS configuration message comprises anidentifier of the radio node and indicates a pattern of sub-subframes inwhich a resource allocation for the radio node repeats.

In some embodiments, configuring the radio node for sub-subframe-basedSPS comprises configuring the radio node for sub-subframe-based SPS thatis concurrent with subframe-based SPS in which a subframe-based resourceallocation repeats according to a further pattern.

In some embodiments, the SPS configuration instructs the radio node toprioritize either the resource allocation or a subframe-based resourceallocation of the radio node with respect to any overlap between theresource allocations.

In some embodiments, the SPS configuration message further comprises aperiod indicating the pattern of sub-subframes in which the resourceallocation repeats.

In some embodiments, the method further comprises determining a HybridAutomatic Repeat Request (HARQ) process identifier corresponding to adata transmission on a particular sub-subframe, wherein determining theHARQ process identifier is based on a position of the particularsub-subframe within a comprising subframe. In some such embodiments,determining the HARQ process identifier based on the position of theparticular sub-subframe within the comprising subframe comprisesdetermining the HARQ process identifier according to:

HARQ ProcessID=[floor(CURRENT_TTI/(semiPersistSchedIntervalUL*SSFs))]modulonumberOfConfUISPS-Processes;

CURRENT_TTI=[(SFN*10*SSFs)+(sub_num*SSFs)+ssf_pos];

-   -   semiPersistSchedIntervalUL is a subframe-based SPS period;    -   SSFs is a number sub-subframes within the subframe;    -   numberOfConfUISPS-Processes is a total number of HARQ process        identifiers configured;    -   SFN is a system frame number;    -   sub_num is an index of the subframe within a larger frame        structure; and    -   ssf_pos is an index of the particular sub-subframe within the        subframe.

In some embodiments, the method further comprises transmitting HARQfeedback to the radio node on a subframe Physical Downlink ControlChannel (PDCCH), wherein the feedback is addressed to the identifier ofthe radio node and further comprises a New Data Indicator set to one.

In some embodiments, the method further comprises transmitting, to theradio node, an SPS activation message instructing the radio node toactivate SPS for sub-subframe-based SPS according to the SPSconfiguration message, the SPS activation message comprising theresource allocation addressed to the identifier of the radio node. Insome such embodiments, the SPS activation message further instructs theradio node to transmit acknowledgement of the SPS activation message ina starting or subsequent sub-subframe in which SPS is activated, and themethod further comprises receiving the acknowledgement of the SPSactivation message in a Medium Access Control (MAC) control elementaccording to the SPS activation message. In some such embodiments,receiving the acknowledgement of the SPS activation message comprisesreceiving the MAC control element via a subframe Physical Uplink SharedChannel (PUSCH).

Other embodiments include a method of transmission schedulingimplemented by a radio node. The method comprises receiving, from ascheduling node, an SPS configuration message comprising an identifierof the radio node and indicating a pattern of sub-subframes in which aresource allocation for the radio node repeats. The method furthercomprises configuring the radio node for sub-subframe-based SPSaccording to the SPS configuration message.

In some embodiments, configuring the radio node for sub-subframe-basedSPS comprises configuring the radio node for sub-subframe based SPS thatis concurrent with subframe-based SPS in which a subframe-based resourceallocation repeats according to a further pattern.

In some embodiments, the SPS configuration instructs the radio node toprioritize either the resource allocation or a subframe-based resourceallocation of the radio node with respect to any overlap between theresource allocations.

In some embodiments, the SPS configuration message further comprises aperiod indicating the pattern of sub-subframes in which the resourceallocation repeats.

In some embodiments, the method further comprises determining a HybridAutomatic Repeat Request (HARQ) process identifier corresponding to adata transmission on a particular sub-subframe, wherein determining theHARQ process identifier is based on a position of the particularsub-subframe within a comprising subframe. In some such embodiments,determining the HARQ process identifier based on the position of theparticular sub-subframe within the comprising subframe comprisesdetermining the HARQ process identifier according to:

HARQ ProcessID=[floor(CURRENT_TTI/(semiPersistSchedIntervalUL*SSFs))]modulonumberOfConfUISPS-Processes;

CURRENT_TTI=[(SFN*10*SSFs)+(sub_num*SSFs)+ssf_pos];

-   -   semiPersistSchedIntervalUL is a subframe-based SPS period;    -   SSFs is a number sub-subframes within the subframe;    -   numberOfConfUISPS-Processes is a total number of HARQ process        identifiers configured;    -   SFN is a system frame number;    -   sub_num is an index of the subframe within a larger frame        structure; and    -   ssf_pos is an index of the particular sub-subframe within the        subframe.

In some embodiments, the method further comprises receiving HARQfeedback from the scheduling node on a subframe Physical DownlinkControl Channel (PDCCH), wherein the feedback is addressed to theidentifier of the radio node and further comprises a New Data Indicatorset to one.

In some embodiments, the method further comprises receiving, from thescheduling node, an SPS activation message instructing the radio node toactivate SPS for the sub-subframe-based SPS according to the SPSconfiguration message. The SPS activation message comprises the resourceallocation addressed to the identifier of the radio node. The methodfurther comprises decoding transmissions received from the schedulingnode according to the resource allocation and the pattern. In some suchembodiments, the SPS activation message further instructs the radio nodeto transmit acknowledgement of the SPS activation message in a startingor subsequent sub-subframe in which SPS is activated, and the methodfurther comprises transmitting the acknowledgement of the SPS activationmessage in a Medium Access Control (MAC) control element according tothe SPS activation message. In some such embodiments, transmitting theacknowledgement of the SPS activation message comprises transmitting theMAC control element via a subframe Physical Uplink Shared Channel(PUSCH).

Embodiments also include apparatus, systems, computer program products,software, and/or carriers that correspond to one or more of the methodsdescribed herein.

For example, embodiments include a scheduling node configured totransmit, to a radio node configured for sub-subframe operation, asemi-persistent scheduling (SPS) configuration message configuring theradio node for sub-subframe-based SPS. The SPS configuration messagecomprises an identifier of the radio node and indicates a pattern ofsub-subframes in which a resource allocation for the radio node repeats.

Embodiments further include a radio node configured to receive, from ascheduling node, a semi-persistent scheduling (SPS) configurationmessage comprising an identifier of the radio node and indicating apattern of sub-subframes in which a resource allocation for the radionode repeats. The radio node is also configured to configure the radionode for sub-subframe-based SPS according to the SPS configurationmessage.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example wireless communication system, accordingto one or more embodiments of the present disclosure.

FIG. 2 illustrates an example of downlink physical resources as may beused for Orthogonal Frequency-Division Multiplexing (OFDM)communication, according to one or more embodiments of the presentdisclosure.

FIG. 3 illustrates an example time-domain structure as may be used forOFDM communication, according to one or more embodiments of the presentdisclosure.

FIG. 4 illustrates an example time-domain structure in whichsub-subframe operation in configured, according to one or moreembodiments of the present disclosure.

FIG. 5 illustrates an example time-domain of a downlink in whichsub-subframe SPS is configured and activated, according to one or moreembodiments of the present disclosure.

FIG. 6 illustrates an example time-domain of sub-subframe SPS operationon an uplink, according to one or more embodiments of the presentdisclosure.

FIG. 7 illustrates an example method implemented by a scheduling node,according to one or more embodiments of the present disclosure.

FIG. 8 illustrates an example method implemented by a radio node,according to one or more embodiments of the present disclosure.

FIG. 9 is a block diagram illustrating example hardware of a schedulingnode useful for implementing one or more of the methods describedherein, according to one or more embodiments of the present disclosure.

FIG. 10 is a block diagram illustrating example means, physical units,or software modules of a scheduling node useful for implementing one ormore of the methods described herein, according to one or moreembodiments of the present disclosure.

FIG. 11 is a block diagram illustrating example hardware of a radio nodeuseful for implementing one or more of the methods described herein,according to one or more embodiments of the present disclosure.

FIG. 12 is a block diagram illustrating example means, physical units,or software modules of a radio node useful for implementing one or moreof the methods described herein, according to one or more embodiments ofthe present disclosure.

Note that, as used herein, when a reference numeral comprises a letterdesignation in the drawings, discussion of a specific instance of anillustrated element will use the appropriate corresponding letterdesignation (e.g., radio node 105 a). However, the letter designationwill be omitted in order to refer generically to the illustrated subjectmatter (e.g., discussion of a radio node 105 (generally), rather thandiscussion of particular radio nodes 105 a, 105 b).

DETAILED DESCRIPTION

As will be described in detail below, aspects of the present disclosuremay be implemented entirely as hardware units, entirely as softwaremodules (including firmware, resident software, micro-code, etc.), or asa combination of hardware units and software modules. For example,embodiments of the present disclosure may take the form of anon-transitory computer readable medium storing software instructions inthe form of a computer program that, when executed on a programmabledevice, configures the programmable device to execute the variousmethods described below.

For clarity in understanding the disclosure below, to the extent that“one of” a conjunctive list of items (e.g., “one of A and B”) isdiscussed, the present disclosure refers to one (but not both) of theitems in the list (e.g., an A or a B, but not both A and B). Such aphrase does not refer to one of each of the list items (e.g., one A andone B), nor does such a phrase refer to only one of a single item in thelist (e.g., only one A, or only one B). Similarly, to the extent that“at least one of” a conjunctive list of items is discussed (andsimilarly for “one or more of” such a list), the present disclosurerefers to any item in the list or any combination of the items in thelist (e.g., an A only, a B only, or both an A and a B). Such a phrasedoes not refer to one or more of each of the items in the list (e.g.,one or more of A, and one or more of B).

Turning now to the drawings, FIG. 1 illustrates an example communicationsystem 100 according to one or more embodiments of the presentdisclosure. Although the communication system 100 will be described inthe context of a Long-Term Evolution (LTE) communication network, thediscussion throughout this disclosure may similarly be applied to otherwireless communication systems and/or combinations thereof, includingbut not limited to 5G Next Radio (NR) and/or Wi-Fi.

The communication system 100 comprises a plurality of wirelesscommunication nodes. One of the wireless communication nodes inparticular is a scheduling node 110 that serves a cell 115 to radionodes 105 a-b. In the context of LTE, radio nodes 105 a-b may each bereferred to as a User Equipment (UE), whereas the scheduling node 110may be a base station (such as an eNodeB), for example. Although onlyone scheduling node 110 and two radio nodes 105 a-b are illustrated inFIG. 1, other examples of the communication system 100 may include anynumber of scheduling nodes 110, each of which may serve one or morecells 115 to any number of radio nodes 105. Further, although radionodes 105 a-b have been described in the context of UEs, the radio nodes105 may themselves be base stations (e.g., femtocells, relay basestations), according to other embodiments. Further, scheduling node 110is itself a type of radio node, in that the scheduling node 110 is anetwork node capable of radio communication.

Wireless communication between the scheduling node 110 and each of theradio nodes 105 a-b is performed using radio resources across a time andfrequency domain. LTE in particular uses OFDM in the downlink andDiscrete Fourier Transform (DFT) spread OFDM in the uplink. The basicLTE downlink physical resource can be viewed as a time-frequency grid.FIG. 2 illustrates a portion of an example OFDM time-frequency grid 50for LTE. Generally speaking, the time-frequency grid 50 is divided intoone millisecond subframes. Each subframe includes a number of OFDMsymbols. For a normal cyclic prefix (CP) length, suitable for use insituations where multipath dispersion is not expected to be extremelysevere, a subframe may comprise fourteen OFDM symbols. A subframe maycomprise twelve OFDM symbols if an extended cyclic prefix is used. Inthe frequency domain, the physical resources shown in FIG. 2 are dividedinto adjacent subcarriers with a spacing of 15 kHz. The number ofsubcarriers may vary according to the allocated system bandwidth. Thesmallest element of the time-frequency grid 50 is typically referred toas a resource element, which comprises one OFDM subcarrier during oneOFDM symbol interval.

In LTE systems, data is transmitted to the mobile terminals over adownlink transport channel known as the Physical Downlink Shared Channel(PDSCH). The PDSCH is a time and frequency multiplexed channel shared bya plurality of radio nodes 105. As shown in FIG. 3, the downlinktransmissions are typically organized into ten millisecond radio frames60. Each radio frame 60 typically comprises ten equally-sized subframes62. For purposes of scheduling users to receive downlink transmissions,the downlink time-frequency resources are allocated in units calledresource blocks (RBs). Each resource block typically spans twelvesubcarriers (which may be adjacent or distributed across the frequencyspectrum) and one 0.5 ms slot (one half of one subframe).

A subframe 62 on either an uplink or a downlink between the schedulingnode 110 and a radio node 105 may be further organized intosub-subframes 82, as illustrated in FIG. 4. In the example of FIG. 4, asubframe 62 comprises six sub-subframes 82 a-f. Each sub-subframe 82 a-fmay be its own short transmission interval. In some embodiments, one ormore of the sub-subframes 82 a-f may be used for a control channel or adata channel. In particular, one or more of the sub-subframes 82 a-f maycomprise a short PDSCH (sPDSCH) or short Physical Uplink Shared Channel(sPUSCH), depending on whether the sub-subframe is part of the downlinkor uplink respectively. In one particular example, sub-subframe 82 a maybe used for the PDCCH of subframe 62, and each of the sub-subframes 82b-f may comprise an sPDSCH. In some further embodiments, a sub-subframe82 may comprise a short PDCCH (sPDCCH). Other combinations of usesand/or channels for the sub-subframes may be included in otherembodiments.

Within a cell 115 the scheduling node 110 may dynamically scheduledownlink transmissions to and/or uplink transmissions from one or moreof the radio nodes 105 a-b, according to one or more embodiments. Forsuch dynamic scheduling, the scheduling node 110 may transmit downlinkcontrol information (DCI) in each subframe 62. The DCI identifies one ormore radio nodes 105 that have been scheduled to receive data in thecurrent downlink subframe 62 and the resource blocks on which the datais being transmitted to the scheduled radio nodes 105. The DCI istypically transmitted on the PDCCH or enhanced PDCCH (ePDCCH), e.g., inthe first two, three, or four OFDM symbols in each subframe 62. Theresources on which the data is carried is typically transmitted in acorresponding Physical Downlink Shared Channel (PDSCH).

Scheduling node 110 may additionally or alternatively performsemi-persistent scheduling (SPS) of the downlink and/or uplink,according to one or more embodiments. SPS generally requires lesssignaling overhead than dynamic scheduling. For SPS scheduling, theresource blocks on which data is being transmitted to one or more radionodes 105 is not identified in DCI transmitted in each subframe 62 (asis the case in dynamic scheduling). Rather, the resource blocks may beidentified in DCI transmitted in a particular subframe 62 for multiplesubframes (e.g., the present subframe and one or more subsequentsubframes). According to one or more embodiments, the multiple subframesmay be contiguous or discontiguous. The spacing between subframeoccasions to which the DCI applies may, in some embodiments, be aperiodicity of the SPS. This SPS period may be expressed in terms oftime (e.g., every 10 milliseconds) and/or in terms of subframes (e.g.,every tenth subframe). According to embodiments, this period may beadapted by the scheduling node 110, e.g., by appropriate signaling aswill be discussed below. Further, this period may be of a duration thatis less than, equal to, or greater than the duration of a radio frame60, according to various embodiments.

According to embodiments, the scheduling node 110 may freely switchbetween dynamic scheduling and SPS, and may configure one or more radionodes 105 accordingly (e.g., via Radio Resource Control (RRC) signalingto indicate that SPS of a particular periodicity is to be used).Thereafter, a resource assignment may be sent in DCI to a radio node 105to activate SPS. The radio node 110 may store this DCI and expect adownlink transmission at each SPS occasion accordingly.

According to embodiments of the present disclosure, SPS may beconfigured for sub-subframe-based SPS operation on the downlink and/oruplink. According to sub-subframe-based SPS, scheduled resource blocks(e.g., as identified in DCI transmitted in a particular subframe 62) areapplied to multiple sub-subframes according to a pattern. The pattern ofscheduled sub-subframes may further repeat according to a furthersubframe-based SPS pattern (e.g., periodically).

An example time-domain of a downlink configured for sub-subframe-basedSPS operation is illustrated in the example of FIG. 5. The time-domaincomprises a plurality of subframes 62, each of which comprises aninitial control region 250 (i.e., a PDCCH) and a subsequent data region260 (i.e., a PDSCH). In some embodiments, the scheduling may previouslyhave been dynamic (not shown), such that DCI is transmitted in thecontrol region 250 indicates resources of the corresponding data region260 in which data will be transmitted by the scheduling node 110 to aradio node 105.

According to this example, the scheduling node 110 transmits aconfiguration message 210 via RRC signaling to configure the radio node105 for sub-subframe-based SPS. The configuration message 210 indicatesa periodicity of the SPS (in this example, two subframes). Theconfiguration message 210 also indicates a pattern of sub-subframes inwhich a resource allocation for the radio node 105 repeats (in thisexample, a pattern of five consecutive sub-subframes, signaled in theconfiguration message 210 as a bitmap of 11111). The configurationmessage may also include an identifier of the radio node 105, such as aRadio Network Temporary Identifier (RNTI). Later, according to thisexample, the scheduling node 110 transmits an activation message 220 inthe control region 250 of a subframe 62 to activate thesub-subframe-based SPS (i.e., as configured by the configuration message210) at a future time. In this particular example, activation ispreconfigured to occur in the fourth subframe 62 after the subframe 62carrying the activation message 220. In some other examples, the time toactivation may be configured by the configuration message 210 or byother signaling. This activation may, in some embodiments, switch thescheduling mode of the radio node 105, e.g., if the radio node 105 waspreviously configured for dynamic scheduling.

The activation message 220 includes the resource allocation on whichdata will be transmitted to the radio node 105 according to thesub-subframe pattern in the relevant sub-subframes 82. The schedulingnode 110 then transmits data 240 a in the data region 260 of the fourthsubframe 62 after the subframe 62 carrying the activation message 220(i.e., the first subframe 62 in the initial SPS period 230 a) accordingto the sub-subframe pattern, and continues transmitting data 240 b, 240c in every SPS period 230 b, 230 c thereafter according to thesub-subframe pattern (as configured by the configuration message 210).Accordingly, according to this example, once SPS is activated, the radionode 105 is configured to expect a possible data transmission from thescheduling node 110 in five consecutive sub-subframes 82 every twosubframes 62.

Although activation is preconfigured to occur in the fourth subframe 62after the activation message 220 in the example described above,according to other embodiments the activation message 220 may indicate astarting sub-subframe 82 in which to activate SPS. Embodiments may also,for example, instruct the radio node 105 to transmit acknowledgement ofthe activation message 220 in, e.g., the starting sub-subframe 82 or asub-subframe 82 thereafter. This acknowledgement may be transmitted bythe radio node 105 to the scheduling node 110 in a Medium Access Control(MAC) control element (e.g., via the PUSCH or sPUSCH) in thesub-subframe 82 indicated by the activation message 220.

Although some embodiments may use separate configuration and activationmessages 210, 220 to configure and activate the radio node 105 for SPS,respectively, other embodiments may use a single message to bothconfigure and activate SPS in the radio node. In an example of such anembodiment, the single message to configure and activate SPS may includeDCI identifying the resources on which data will be transmitted, and aduration between instances of subframes carrying such resources (i.e., aperiodicity of the SPS).

Further, the configuration and/or activation message 210, 220 may betransmitted using different channels and/or signaling according to otherembodiments. For example, the configuration and/or activation message210, 220 may be transmitted using a Medium Access Control (MAC) ControlElement, e.g., in a PDSCH or sPDSCH transmission.

Further, although the example of FIG. 5 illustrates an SPS period 250 oftwo subframes, other embodiments include SPS periods 230 of otherdurations. For example, particular radio nodes 105 may have very lowlatency requirements. Such radio nodes 105 may be devices participatingin Critical Machine Type Communication (CMTC), for example. Such asystem may, for example, have an SPS period 250 of less than twosubframes. Less critical systems may have an SPS period 250 of more thantwo subframes but less than 10 milliseconds (i.e., less than one typicalLTE radio frame 60). Systems that involve very infrequent and/or lowpriority communication, for example, may have SPS periods 250 of morethan ten subframes. The SPS period specified by the scheduling node 110may be dependent upon the particular system, devices, and/or conditionsthat are present.

Further, although the example of FIG. 5 illustrates a sub-subframepattern of five consecutive sub-subframes 82, other embodiments mayinclude other patterns and may be represented by other data structures.For example, a pattern of alternating sub-subframes 82 may be indicatedby a corresponding flag. Alternatively, a repeating pattern of periodicsub-subframes may be indicated by specifying a duration of thesub-subframe SPS period (e.g., in terms of time or sub-subframes). Otherpatterns may be randomly selected by the scheduling node 110, forexample, and indicated using respective bitmaps. For example, thepattern of two allocated sub-subframes 82 followed by two non-allocatedsub-subframes may be represented by the bitmap 1100, its decimal integerequivalent 12, or other data structure. In general, embodiments mayinclude a plurality of the sub-subframes that fit within a duration of asingle subframe, and the SPS configuration message 210 may indicate thepattern in which the resource allocation repeats by indicating to whichof the plurality of the sub-subframes 82 the resource allocationapplies.

Further, although the example of FIG. 5 illustrates an example of adownlink configured for sub-subframe-based SPS operation, the uplink maybe similarly configured, as shown in the example of FIG. 6. To configurethe sub-subframe-based SPS operation of FIG. 6, a configuration message210 may include a pattern for the uplink in which a resource allocationfor the radio node 105 repeats on the uplink. In the example of FIG. 6,the uplink pattern is three scheduled sub-subframes 82 followed by twounscheduled sub-subframes 82, which may be represented in the activationmessage 210 using a bitmap of 11100, for example. The configurationmessage 210 may also include an SPS periodicity for the uplink. In thisexample, the SPS periodicity of the uplink is one subframe 62.Accordingly, the example of FIG. 6 shows an uplink configured withmultiple SPS periods 230 d-h, each one subframe 82 in duration, in whichdata is transmitted by the radio node 105 on the uplink according to apattern of three sub-subframes 82, and not transmitted in the followingtwo sub-subframes 82 in each subframe 62.

In view of the example above, particular embodiments may includeproviding control information (e.g., activation, configuration, and/orrelease messages) to the radio node 105 via an sPDCCH of a sub-subframeand/or the PDCCH of a subframe 62. Such control messages may include DCIto provide resource allocation to the radio node 105 according todynamic scheduling, subframe-based SPS, and/or sub-subframe-based SPSoperation. Confirmation of this SPS may be transmitted by the radio node105 using a MAC control element, e.g., in the first granted uplinkresource after the SPS is activated. Any or all of the informationcomprised in any of these control messages may be addressed to the radionode 105 using an identifier of the radio node 105 (e.g., a RadioNetwork Temporary Identifer (RNTI)).

In some embodiments, such control information may configure the radionode 105 for sub-subframe based SPS that is concurrent withsubframe-based SPS. Some such embodiments may include a sub-subframeresource allocation for the sub-subframe-based SPS, and a subframeresource allocation for the concurrent subframe-based SPS. In some suchembodiments, the resource allocations may overlap with respect toparticular resources. Thus, in some such embodiments, the configurationmessage 210 may instruct the radio node 105 to prioritize either thesub-subframe resource allocation or the subframe-based resourceallocation with respect to any such overlap.

Further, in some such embodiments in which sub-subframe-based andsubframe-based SPS is to operate concurrently, the patterns between thetwo may be jointly configurable and/or discerned from one another due toa relationship between their transmission patterns. For example, thescheduling node 110 may transmit a configuration message 210 to theradio node 105 that indicates a subframe-based SPS period of twosubframes 62, and that sub-subframe-based SPS should also be used, i.e.,without explicitly stating what sub-subframe-based SPS pattern the radionode 105 is to use. In some such embodiments, the radio node 105determines the sub-subframe-based SPS pattern based on thesubframe-based SPS pattern. For example, if the subframe-based SPS isconfigured to use an SPS period 230 of two subframes, the radio node 105may determine that the pattern for sub-subframe-based SPS shouldsimilarly use a periodic two sub-subframe 82 interval. Similarly, thetransmission node 110 may configure the pattern of sub-subframesaccording to subframe-based SPS period. Other relationships betweensubframe-based and sub-subframe-based SPS are also included in otherembodiments.

As discussed above, the scheduling node 110 may be serving multipleradio nodes 105. In particular, the scheduling node 110 may grantresource allocations to each of the radio nodes 105 a-b. In some suchcases, the scheduling node 110 may coordinate the resource allocationsof different radio nodes 105 a-b to prevent or limit overlap. In someembodiments, the scheduling node 100 randomly selects the plurality ofthe sub-subframes to which the resource allocation applies for each ofthe resource allocations. While this random selection may not completelyeliminate overlap (in some embodiments), such random selection mayreduce the likelihood of overlap while being computationally efficient(e.g., such an approach may avoid the need for complex algorithms tolocate unallocated resources and signal an appropriate pattern to theradio nodes 105 a-b).

The scheduling node 110 may take further measures to resolve overlappingresource assignments in one or more embodiments in which such overlapsmay occur. For example, in some embodiments, the scheduling node 110 mayscramble each of a plurality of sPDSCH transmissions with the identifierof the radio node (e.g., RNTI) to which the sPDSCH transmission isintended. Thus, the transmission node 110 may scramble an sPDSCHtransmission intended for radio node 105 a with an RNTI of that radionode 105, for example. Other embodiments may resolve overlappingresource allocation by scrambling the cyclic redundancy check (CRC) codecorresponding to the sPDSCH transmission, e.g., using the identifier ofthe radio node 105 to which the sPDSCH transmission is intended. Thus,the transmission node 110 may scramble a CRC corresponding to a furthersPDSCH transmission intended for radio node 105 b with an RNTI of thatradio node 105, and transmit the scrambled CRC. In such embodiments, aradio node 105 may, e.g., descramble the scrambled data received andattempt to perform a CRC check. If the CRC check is successful, thesPDSCH transmission may be considered to be directed to that radio node105. If not, the sPDSCH transmission may be erroneous or intended for adifferent radio node 105.

Some embodiments use Hybrid Automatic Repeat Request (HARQ) on theuplink and/or downlink. During dynamic scheduling, a HARQ processidentifier is typically specified in the control region 250 of eachsubframe 62 for use with data transmission and/or HARQ feedback.However, such information may not be in each subframe under SPSoperation. Accordingly, in some embodiments, the radio node 105 and/orscheduling node 110 may determine a HARQ process identifier on theirown. In particular, in some embodiments, the radio node 105 andscheduling node 110 each determine a HARQ process identifier for datatransmission in a consistent manner, such that each can independentlydetermine the HARQ process identifier without having to signal thisinformation. For example, the radio node 105 and/or scheduling node 110may use a formula to derive the HARQ process identifier from, e.g., asystem frame number, subframe number, and/or other parameters known toboth the radio node 105 and scheduling node 110. As one particularexample, the HARQ process identifier may be determined according to theformula:

HARQ ProcessID=[floor(CURRENT_TTI/(semiPersistSchedIntervalUL*SSFs))]modulonumberOfConfUISPS-Processes

In this example formula CURRENT_TTI is given by the formula:

CURRENT_TTI=[(SFN*10*SSFs)+(sub_num*SSFs)+ssf_pos]

In the formulas above, semiPersistSchedIntervalUL may be asubframe-based SPS period; SSFs may be a number sub-subframes within thesubframe; numberOfConfUISPS-Processes may be a total number of HARQprocess identifiers configured; SFN may be a system frame number;sub_num may be an index of the subframe within a larger frame structure;and ssf_pos may be an index of the particular sub-subframe within thesubframe. Other formula may additionally or alternatively be used.

Consistent with the above, HARQ feedback may be transmitted by thescheduling node 110 to a radio node 105 on the sPDCCH or PDCCH,according to embodiments. In particular embodiments, the feedbackcomprises a bitmap of previous sub-subframes 82 of thesub-subframe-based SPS, each bit of the bitmap indicating whether or notretransmission of a previous transmission on the correspondingsub-subframe 82 is requested from the radio node 105. Such feedback may,for example, be addressed to the identifier of the radio node and mayfurther comprise a New Data Indicator set to one, e.g., to indicate thata retransmission is requested. The HARQ scheme used may, for example,use the sPDCCH to schedule such retransmissions. As this sPDCCH may bean in-band control channel, the location of the sPDCCH may be includedin the configuration message 210, according to embodiments.

In view of the above, embodiments of the present disclosure include theexample method 300 of transmission scheduling illustrated in FIG. 7. Themethod 300 may be implemented by a scheduling node 110 and comprisestransmitting, to a radio node 105 configured for sub-subframe operation,an SPS configuration message 210 configuring the radio node 105 forsub-subframe-based SPS (block 320). The SPS configuration message 210comprises an identifier of the radio node 105 and indicates a pattern ofsub-subframes 82 in which a resource allocation for the radio node 105repeats. According to some embodiments of such an example method 300,the method 300 may further comprise configuring the radio node 105 forsubframe-based SPS (block 310), and transmitting the SPS configurationmessage 210 configuring the radio node 105 for sub-subframe-based SPS inresponse (block 320).

Other embodiments of the present disclosure include the example method400 of transmission scheduling illustrated in FIG. 8. The method 400 maybe implemented by a radio node 105 and comprises receiving, from ascheduling node 110, an SPS configuration message 210 comprising anidentifier of the radio node 105 and indicating a pattern ofsub-subframes 82 in which a resource allocation for the radio node 105repeats (block 410). The method 400 further comprises configuring theradio node 105 for sub-subframe-based SPS according to the SPSconfiguration message 210 (block 420).

Note that a scheduling node 110 and/or radio node 105 as described abovemay perform any of the methods described herein (and any otherprocessing herein) by implementing any functional means, units, ormodules. In one embodiment, for example, the scheduling node 110comprises respective circuits or circuitry configured to perform thesteps of method 300 shown in FIG. 7. In another embodiment, for example,the radio node 105 comprises respective circuits or circuitry configuredto perform the steps of method 400 shown in FIG. 8. The circuits orcircuitry in this regard may comprise circuits dedicated to performingcertain functional processing and/or may comprise one or moremicroprocessors in conjunction with memory. In embodiments that employmemory, which may comprise one or several types of memory such asread-only memory (ROM), random-access memory, cache memory, flash memorydevices, optical storage devices, etc., the memory may store programcode that, when executed by the one or more processors, carries out thetechniques described herein.

FIG. 9 illustrates an example scheduling node 110, implemented inaccordance with one or more embodiments. As shown, the scheduling node110 includes processing circuitry 510 and communication circuitry 530.The communication circuitry 530 is configured to transmit and/or receiveinformation to and/or from one or more other nodes, e.g., via anycommunication technology. Such communication may occur via one or moreantennas that are either internal or external to the scheduling node110. The processing circuitry 510 is configured to perform processingdescribed above, e.g., in FIG. 7, such as by executing instructionsstored in memory 520. The processing circuitry 510 in this regard mayimplement certain functional means, units, or modules.

FIG. 10 illustrates an example scheduling node 110, implemented inaccordance with one or more other embodiments. As shown, the schedulingnode 110 implements various functional means, units, or modules, e.g.,via the processing circuitry 510 in FIG. 9 and/or via software code.These functional means, units, or modules, e.g., for implementing themethod 300 in FIG. 7, include for instance a configuring unit or module610 for configuring a radio node configured for subframe-based SPS, insome embodiments. Additionally or alternatively included is atransmitting unit or module 620 for transmitting, to a radio node 105configured for sub-subframe operation, an SPS configuration message 210configuring the radio node 105 for sub-subframe-based SPS. The SPSconfiguration message 210 comprises an identifier of the radio node 105and indicates a pattern of sub-subframes 82 in which a resourceallocation for the radio node 105 repeats.

FIG. 11 illustrates an example radio node 105, implemented in accordancewith one or more embodiments. As shown, the radio node 105 includesprocessing circuitry 710 and communication circuitry 730. Thecommunication circuitry 730 is configured to transmit and/or receiveinformation to and/or from one or more other nodes, e.g., via anycommunication technology. Such communication may occur via one or moreantennas that are either internal or external to the radio node 105. Theprocessing circuitry 710 is configured to perform processing describedabove, e.g., in FIG. 8, such as by executing instructions stored inmemory 720. The processing circuitry 710 in this regard may implementcertain functional means, units, or modules.

FIG. 12 illustrates an example radio node 105, implemented in accordancewith one or more other embodiments. As shown, the radio node 105implements various functional means, units, or modules, e.g., via theprocessing circuitry 710 in FIG. 11 and/or via software code. Thesefunctional means, units, or modules, e.g., for implementing the method400 in FIG. 8, include for instance a receiving unit or module 810 forreceiving, from a scheduling node 110, an SPS configuration message 210comprising an identifier of the radio node 105 and indicating a patternof sub-subframes 82 in which a resource allocation for the radio node105 repeats. Also included is a configuring unit or module 820 forconfiguring the radio node 105 for sub-subframe-based SPS according tothe SPS configuration message 210.

Those skilled in the art will also appreciate that embodiments hereinfurther include methods and devices that initiate any of the methodsdescribed above, e.g., via one or more corresponding control commandsissued over an appropriate signaling medium.

Those skilled in the art will also appreciate that embodiments hereinfurther include corresponding computer programs.

Embodiments further include a computer program that comprisesinstructions which, when executed on at least one processor of ascheduling node 110 or radio node 105, cause the scheduling node 110 orradio node 105 to carry out any of the respective processing describedabove. A computer program in this regard may comprise one or more codemodules corresponding to the means or units described above.

Embodiments further include a carrier containing such a computerprogram. This carrier may comprise one of an electronic signal, opticalsignal, radio signal, or computer readable storage medium.

In this regard, embodiments herein also include a computer programproduct stored on a non-transitory computer readable (storage orrecording) medium and comprising instructions that, when executed by aprocessor of a scheduling node 110 or radio node 105, cause thescheduling node 110 or radio node 105 to perform as described above.

Embodiments further include a computer program product comprisingprogram code portions for performing the steps of any of the embodimentsherein when the computer program product is executed by a schedulingnode 110 or radio node 105. This computer program product may be storedon a computer readable recording medium.

The present disclosure may be carried out in other ways than thosespecifically set forth herein without departing from the essentialcharacteristics thereof. For example, additional physical units orsoftware modules may be included in the various embodiments to performany of the additional functions discussed above. The present embodimentsare to be considered in all respects as illustrative and notrestrictive, and all changes coming within the meaning and equivalencyrange of the appended claims are intended to be embraced therein.

1-34. (canceled)
 35. A method of transmission scheduling implemented bya scheduling node, the method comprising the scheduling node:transmitting, to a radio node configured for sub-subframe operation, asemi-persistent scheduling (SPS) configuration message configuring theradio node for sub-subframe-based SPS; wherein the SPS configurationmessage comprises an identifier of the radio node and indicates apattern of sub-subframes in which a resource allocation for the radionode repeats.
 36. The method of claim 34, wherein configuring the radionode for sub-subframe-based SPS comprises configuring the radio node forsub-subframe-based SPS that is concurrent with subframe-based SPS inwhich a subframe-based resource allocation repeats according to afurther pattern.
 37. The method of claim 36, wherein the SPSconfiguration message instructs the radio node to prioritize either theresource allocation or a subframe-based resource allocation of the radionode with respect to any overlap between the resource allocations. 38.The method of claim 34, wherein the SPS configuration message furthercomprises a period indicating the pattern of sub-subframes in which theresource allocation repeats.
 39. The method of claim 34, furthercomprising determining a Hybrid Automatic Repeat Request (HARQ) processidentifier corresponding to a data transmission on a particularsub-subframe, wherein the determining the HARQ process identifier isbased on a position of the particular sub-subframe within a comprisingsubframe.
 40. The method of claim 39, wherein determining the HARQprocess identifier based on the position of the particular sub-subframewithin the comprising subframe comprises determining the HARQ processidentifier according to:HARQ ProcessID=[floor(CURRENT_TTI/(semiPersistSchedIntervalUL*SSFs))]modulonumberOfConfUISPS-Processes; whereinCURRENT_TTI=[(SFN*10*SSFs)+(sub_num*SSFs)+ssf_pos]; whereinsemiPersistSchedIntervalUL is a subframe-based SPS period; wherein SSFsis a number sub-subframes within the subframe; whereinnumberOfConfUISPS-Processes is a total number of HARQ processidentifiers configured; wherein SFN is a system frame number; whereinsub_num is an index of the subframe within a larger frame structure;wherein ssf_pos is an index of the particular sub-subframe within thesubframe.
 41. The method of claim 34, further comprising transmittingHARQ feedback to the radio node on a sub-subframe short PhysicalDownlink Control Channel (sPDCCH), wherein the feedback is addressed tothe identifier of the radio node and further comprises a New DataIndicator set to one.
 42. The method of claim 34, further comprisingtransmitting, to the radio node, an SPS activation message instructingthe radio node to activate SPS for sub-subframe-based SPS according tothe SPS configuration message, the SPS activation message comprising theresource allocation addressed to the identifier of the radio node. 43.The method of claim 42: wherein the SPS activation message furtherinstructs the radio node to transmit acknowledgement of the SPSactivation message in a starting or subsequent sub-subframe in which SPSis activated; and wherein the method further comprises receiving theacknowledgement of the SPS activation message in a Medium Access Control(MAC) control element according to the SPS activation message.
 44. Themethod of claim 43, wherein the receiving the acknowledgement of the SPSactivation message comprises receiving the MAC control element via asubframe Physical Uplink Shared Channel (PUSCH).
 45. A scheduling node,comprising: processing circuitry; memory containing instructionsexecutable by the processing circuitry whereby the scheduling node isoperative to: transmit, to a radio node configured for sub-subframeoperation, a semi-persistent scheduling (SPS) configuration messageconfiguring the radio node for sub-subframe-based SPS; wherein the SPSconfiguration message comprises an identifier of the radio node andindicates a pattern of sub-subframes in which a resource allocation forthe radio node repeats.
 46. A method of transmission schedulingimplemented by a radio node, the method comprising the radio node:receiving, from a scheduling node, a semi-persistent scheduling (SPS)configuration message comprising an identifier of the radio node andindicating a pattern of sub-subframes in which a resource allocation forthe radio node repeats; and configuring the radio node forsub-subframe-based SPS according to the SPS configuration message. 47.The method of claim 46, wherein the configuring the radio node forsub-subframe-based SPS comprises configuring the radio node forsub-subframe-based SPS that is concurrent with subframe-based SPS inwhich a subframe-based resource allocation repeats according to afurther pattern.
 48. The method of claim 47, wherein the SPSconfiguration message instructs the radio node to prioritize either theresource allocation or a subframe-based resource allocation of the radionode with respect to any overlap between the resource allocations. 49.The method of claim 46, wherein the SPS configuration message furthercomprises a period indicating the pattern of sub-subframes in which theresource allocation repeats.
 50. The method of claim 46, furthercomprising determining a Hybrid Automatic Repeat Request (HARQ) processidentifier corresponding to a data transmission on a particularsub-subframe, wherein the determining the HARQ process identifier isbased on a position of the particular sub-subframe within a comprisingsubframe.
 51. The method of claim 50, wherein determining the HARQprocess identifier based on the position of the particular sub-subframewithin the comprising subframe comprises determining the HARQ processidentifier according to:HARQ ProcessID=[floor(CURRENT_TTI/(semiPersistSchedIntervalUL*SSFs))]modulonumberOfConfUISPS-Processes; whereinCURRENT_TTI=[(SFN*10*SSFs)+(sub_num*SSFs)+ssf_pos]; whereinsemiPersistSchedIntervalUL is a subframe-based SPS period; wherein SSFsis a number sub-subframes within the subframe; whereinnumberOfConfUISPS-Processes is a total number of HARQ processidentifiers configured; wherein SFN is a system frame number; whereinsub_num is an index of the subframe within a larger frame structure;wherein ssf_pos is an index of the particular sub-subframe within thesubframe.
 52. The method of claim 50, further comprising receiving HARQfeedback from the scheduling node on a sub-subframe short PhysicalDownlink Control Channel (sPDCCH), wherein the feedback is addressed tothe identifier of the radio node and further comprises a New DataIndicator set to one.
 53. The method of claim 46, further comprising:receiving, from the scheduling node, an SPS activation messageinstructing the radio node to activate SPS for the sub-subframe-basedSPS according to the SPS configuration message, the SPS activationmessage comprising the resource allocation addressed to the identifierof the radio node; decoding transmissions received from the schedulingnode according to the resource allocation and the pattern.
 54. Themethod of claim 53: wherein the SPS activation message further instructsthe radio node to transmit acknowledgement of the SPS activation messagein a starting or subsequent sub-subframe in which SPS is activated; andwherein the method further comprises transmitting the acknowledgement ofthe SPS activation message in a Medium Access Control (MAC) controlelement according to the SPS activation message.
 55. The method of claim25, wherein the transmitting the acknowledgement of the SPS activationmessage comprises transmitting the MAC control element via a subframePhysical Uplink Shared Channel (PUSCH).
 56. A radio node, comprising:processing circuitry; memory containing instructions executable by theprocessing circuitry whereby the radio node is operative to: receive,from a scheduling node, a semi-persistent scheduling (SPS) configurationmessage comprising an identifier of the radio node and indicating apattern of sub-subframes in which a resource allocation for the radionode repeats; and configure the radio node for sub-subframe-based SPSaccording to the SPS configuration message.
 57. A non-transitorycomputer readable recording medium storing a computer program productfor transmission scheduling implemented by a scheduling node, thecomputer program product comprising software instructions which, whenrun on processing circuitry of a scheduling node, causes the schedulingnode to: transmit, to a radio node configured for sub-subframeoperation, a semi-persistent scheduling (SPS) configuration messageconfiguring the radio node for sub-subframe-based SPS; wherein the SPSconfiguration message comprises an identifier of the radio node andindicates a pattern of sub-subframes in which a resource allocation forthe radio node repeats.
 58. A non-transitory computer readable recordingmedium storing a computer program product for transmission schedulingimplemented by a radio node, the computer program product comprisingsoftware instructions which, when run on processing circuitry a radionode, causes the radio node to: receive, from a scheduling node, asemi-persistent scheduling (SPS) configuration message comprising anidentifier of the radio node and indicating a pattern of sub-subframesin which a resource allocation for the radio node repeats; and configurethe radio node for sub-subframe-based SPS according to the SPSconfiguration message.